Umm... if you are driving North from Seohyun on the big main road through town, keep going until you pass Imae station. Soon after that, you will see an SK gas station on your right. Keep going through that light. I believe the next intersection has an over/underpass. (NOTE: You will have just passed the new Seongnam Arts Center and Taewon High School on the right). Get in the right lane(don't take the underpass -- take the over) and turn right at that intersection. Go straight about 100 meters to the stop light. Go through that stoplight, and then the next (you are now passing the library). Just past the library entrance, on the right-hand side, is Hard-Off, tucked in behind a few restaurants. You can catch a glimpse of the blue/yellow sign written in English.